Youssouf Djaoro as Adam in A Screaming Man: ‘a performance of immense dignity’.

When the name of the landlocked African republic of Chad comes up, most cinephiles will think of the opening of Antonioni's The Passenger. In that masterly 1975 film, playing a reporter at the end of his tether while covering a hopeless civil war, Jack Nicholson swaps his identity with a dead man he finds in a remote Saharan hotel. It seems to sum up the sense of desperation and extreme experience that, rightly or wrongly, Chad incites.

However, as in other troubled, desperately poor African countries, there are a handful of gifted artists of world stature, mostly musicians but also painters and film-makers, and A Screaming Man, the fourth feature film by Mahamat-Saleh Haroun, Chad's only prominent film-maker, won the jury prize at last year's Cannes film festival. This year Haroun is serving on the festival jury under Robert De Niro and later this month he's to be the subject of a brief retrospective season at BFI South Bank, or the National Film Theatre as some of us insist on calling it. For many years Chad hasn't had a cinema, so making a movie there is rather like cutting a key without having a lock to use it on. But – a hopeful sign – an old cinema has been reopened and renovated to show Haroun's movies.

Although having lived in France for 30 years after receiving severe war wounds, the 50-year-old Haroun has set all his films in Chad. There's a theme running through the simple, deeply affecting Abouna and Daratt, the previous films by Haroun that have been released in this country, of families falling apart under the strain of war and poverty. In Abouna, a previously dedicated father suddenly disappears from the family in Chad's capital of N'djamena; in Daratt, a young man is dispatched by his blind grandfather to find and kill his father's murderer after a general amnesty has been decreed following 40 years of civil war. This theme is also pursued in A Screaming Man, where social insecurity, poverty and an ever-widening civil war tear a family apart.

All his films are financed in Europe, and A Screaming Man clearly has a European model in FW Murnau's silent classic The Last Laugh (aka Der letzte Mann). Scripted by Carl Mayer (the only truly great writer to work exclusively in the cinema and now buried in Highgate cemetery), The Last Laugh centres on a pompous doorman at a grand hotel in Berlin humiliated by being reduced to working as a lavatory attendant. In Haroun's version he becomes Adam, a 55-year-old swimming-pool attendant at a smart hotel for upper-class guests, mainly foreigners. A former national swimming star known to everyone as "Champ", he has the stiff, proud bearing of a regimental sergeant major and is assisted by his handsome westernised son, 20-year-old Ahmed.

But with fluctuating fortunes in war-torn times, the hotel's new manager, Mrs Wang, is laying off staff and Adam is given the less dignified and remunerated job of gatekeeper. Ahmed is promoted to running the pool and is clearly more popular with female clients. A rift is created between them, and in a beautifully modulated scene shot in a single take, Mariam, the mother of the family, tries to keep the peace.

A Screaming Man doesn't have the expressionistic force of The Last Laugh, but it does have a performance of immense dignity from Youssouf Djaoro as Adam, whose biblical name becomes increasingly appropriate as the film proceeds. It also develops Carl Mayer's story far beyond anything in the original. Through the pressures working on Adam and the demands of a country involved in a pointless war, the young Ahmed is quite literally dragged away to war, and Adam is restored to his old post. This job, however, becomes increasingly unimportant.

The war is never viewed directly. It is something happening across the desert, but getting ever closer. Wounded soldiers appear in the street; UN troops use the pool. The noise of airliners overhead is replaced by that of military aircraft. The guilt-stricken Adam and his kindly wife take in a pregnant singer from Mali, Ahmed's 19-year-old girlfriend they had never heard of. A curfew is called as the town degenerates into anarchy. Having felt betrayed by his employees, Adam is now haunted by having himself become a traitor in a society given over to self-interest. He thus sets out to do the honest, upright thing. His task is to make moral sense of his life in a chaotic world where morality was once established through the position he held in an ordered, hieratic community.

A Screaming Man is a quiet film about family life, the relationship between fathers and children, and the way generations can shape and reshape each other. It ultimately has a sublime quality. The spirit of such quiet, reflective directors as Ozu and Bresson lies behind it and there are no sudden cuts or startling images.

The dominant motif is water. Father and son compete as swimmers. The pool and the river are places of escape from this harsh desert world. Water is not only a precious commodity for survival, but also a religious element for immersion and spiritual cleansing. Appropriately, A Screaming Man begins and ends with Adam in the water which has taken on a divine, healing quality in the course of the film.